[Tom Line]

Are you trying to bend the rod, or not?

You can drill it and it will splinter a bit. Your best bet is to wrap it in tape prior to the drilling. Drill with a very sharp bit, then when you're done remove the tape gently and coat the hole walls with a good epoxy to prevent further splintering and cracking.

If you're just looking to raise a lightweight hook up to the bar, you should be able to do that easily with .5".

Sometimes using a very thin (1/32 or 1/64) aluminum or brass sleeve and glueing it in place prior to drilling will prevent the splintering entirely AND keep the tube stable afterwards.

Edit: It's still good practice to coat the walls of the hole with epoxy even if you've sleeved it.